[flang][driver] Refactor boolean options

For boolean options, e.g. `-fxor-operator`/`-fno-xor-operator`, we ought
to be using TableGen multi-classes. This way, we only have to write one
definition to have both forms auto-generated. This patch refactors all
of Flang's boolean options to use two new multi-classes:
`OptInFC1FFOption` and `OptOutFC1FFOption`. These multi-classes are
based on `OptInFFOption`/`OptOutFFOption`, respectively. I've also
simplified the processing of the updated options in
CompilerInvocation.cpp.

With the new approach, "empty" help text (i.e. no `HelpText`) is now
replaced with an empty string (i.e. HelpText<"">). When running
flang-new --help, that's considered as non-empty help messages, which is
then printed (that's controlled by `printHelp` from
llvm/lib/Option/OptTable.cpp). This means that with this patch,
flang-new --help will start printing e.g. -fno-backslash, even though
there is no actual help text to print for this option (apart from the
empty string ""). Tests are updated accordingly.

Note that with this patch, both `-fxor-operator` and `-fno-xor-operator`
(and other boolean options refactored here) remain available in
`flang-new` and `flang-new -fc1`. In this respect, nothing changes. In a
forthcoming patch, I will refine this so that `flang-new -fc1` only
accepts `-ffoo` (`OptInFC1FFOption`) or `-fno-foo` (`OptOutCC1FFOption`).

For clarity, `OptInFFOption`/`OptOutFFOption` are renamed as
`OptInCC1FFOption`/`OptOutCC1FFOption`, respectively. Otherwise, this is
an NFC from Clang's perspective.

Differential Revision: https://reviews.llvm.org/D105881

1 files changed, 25 insertions, 31 deletions

diff --git a/flang/lib/Frontend/CompilerInvocation.cpp b/flang/lib/Frontend/CompilerInvocation.cpp
index fb0a21e..68ff1671 100644
--- a/flang/lib/Frontend/CompilerInvocation.cpp
+++ b/flang/lib/Frontend/CompilerInvocation.cpp
@@ -277,32 +277,27 @@ static bool ParseFrontendArgs(FrontendOptions &opts, llvm::opt::ArgList &args,
     }
   }
 
-  if (const llvm::opt::Arg *arg =
-          args.getLastArg(clang::driver::options::OPT_fimplicit_none,
-              clang::driver::options::OPT_fno_implicit_none)) {
-    opts.features.Enable(
-        Fortran::common::LanguageFeature::ImplicitNoneTypeAlways,
-        arg->getOption().matches(clang::driver::options::OPT_fimplicit_none));
-  }
-  if (const llvm::opt::Arg *arg =
-          args.getLastArg(clang::driver::options::OPT_fbackslash,
-              clang::driver::options::OPT_fno_backslash)) {
-    opts.features.Enable(Fortran::common::LanguageFeature::BackslashEscapes,
-        arg->getOption().matches(clang::driver::options::OPT_fbackslash));
-  }
-  if (const llvm::opt::Arg *arg =
-          args.getLastArg(clang::driver::options::OPT_flogical_abbreviations,
-              clang::driver::options::OPT_fno_logical_abbreviations)) {
-    opts.features.Enable(Fortran::common::LanguageFeature::LogicalAbbreviations,
-        arg->getOption().matches(
-            clang::driver::options::OPT_flogical_abbreviations));
-  }
-  if (const llvm::opt::Arg *arg =
-          args.getLastArg(clang::driver::options::OPT_fxor_operator,
-              clang::driver::options::OPT_fno_xor_operator)) {
-    opts.features.Enable(Fortran::common::LanguageFeature::XOROperator,
-        arg->getOption().matches(clang::driver::options::OPT_fxor_operator));
-  }
+  // -f{no-}implicit-none
+  opts.features.Enable(
+      Fortran::common::LanguageFeature::ImplicitNoneTypeAlways,
+      args.hasFlag(clang::driver::options::OPT_fimplicit_none,
+          clang::driver::options::OPT_fno_implicit_none, false));
+
+  // -f{no-}backslash
+  opts.features.Enable(Fortran::common::LanguageFeature::BackslashEscapes,
+      args.hasFlag(clang::driver::options::OPT_fbackslash,
+          clang::driver::options::OPT_fno_backslash, false));
+
+  // -f{no-}logical-abbreviations
+  opts.features.Enable(Fortran::common::LanguageFeature::LogicalAbbreviations,
+      args.hasFlag(clang::driver::options::OPT_flogical_abbreviations,
+          clang::driver::options::OPT_fno_logical_abbreviations, false));
+
+  // -f{no-}xor-operator
+  opts.features.Enable(Fortran::common::LanguageFeature::XOROperator,
+      args.hasFlag(clang::driver::options::OPT_fxor_operator,
+          clang::driver::options::OPT_fno_xor_operator, false));
+
   if (args.hasArg(
           clang::driver::options::OPT_falternative_parameter_statement)) {
     opts.features.Enable(Fortran::common::LanguageFeature::OldStyleParameter);
@@ -406,11 +401,10 @@ static bool parseSemaArgs(CompilerInvocation &res, llvm::opt::ArgList &args,
     res.SetModuleFileSuffix(moduleSuffix->getValue());
   }
 
-  // -fno-analyzed-objects-for-unparse
-  if (args.hasArg(
-          clang::driver::options::OPT_fno_analyzed_objects_for_unparse)) {
-    res.SetUseAnalyzedObjectsForUnparse(false);
-  }
+  // -f{no-}analyzed-objects-for-unparse
+  res.SetUseAnalyzedObjectsForUnparse(
+      args.hasFlag(clang::driver::options::OPT_fanalyzed_objects_for_unparse,
+          clang::driver::options::OPT_fno_analyzed_objects_for_unparse, true));
 
   return diags.getNumErrors() == numErrorsBefore;
 }